and walk continually in love [that is, value one another—practice empathy and compassion, unselfishly seeking the best for others], just as Christ also loved you and gave Himself up for us, an offering and sacrifice to God [slain for you, so that it became] a sweet fragrance. (AMP)
As Christians we should walk in love, with agape love that Christ did. Agape love is sacrificial, unselfish, unconditional love that proves itself through actions.
Agape love perfectly describes God’s love for us. He gave Himself up for us on the cross. That is the Christ's sacrifice made on our behalf. The sacrifice here is described as fragrant offering.
Our heartfelt songs and prayers are like fragrant offerings. And also, the words we share about Him and the deeds we offer in His name spread sweet-smelling aroma.
When we follow Jesus, we walk in His love and spread His sweet aroma to others.